What is its ontological meaning? By asking this, we have given an unequivocal direction to our inquiry.
But is this a way of asking ontologically about the 'world' ? The problematic which we have thus marked out is one which is undoubtedly ontological. But even if this ontology should itself succeed in explicating the Being of Nature in the very purest manner, in conformity with the basic assertions about this entity, which the mathematical natural sciences provide, it will never reach the phenomenon that is the 'world'. Nature is itself an entity which is encountered within the world and which can be discovered in various ways and at various stages.
Should we then first attach ourselves to those entities with which Dasein proximally and for the most part dwells—Things 'invested with value' ? Do not these 'really' show us the world in which we live ? Perhaps,  in fact, they show us something like the 'world' more penetratingly. But these Things too are entities 'within' the world.
Neither the ontical depiction of entities within-the-world nor the ontological Interpretation of their Being is such as to reach the phenomenon of the 'world.' In both of these ways of access to 'Objective Being', the 'world' has already been 'presupposed', and indeed in various ways.
Is it possible that ultimately we cannot address ourselves to 'the world' as determining the nature of the entity we have mentioned? Yet we call this entity one which is "within-the-world". Is 'world' perhaps a characteristic of Dasein's Being ? And in that case, does every Dasein 'proximally' have its world ? Does not 'world' thus become something 'subjective'? How, then, can there be a 'common' world 'in' which, nevertheless, we are? And if we raise the question of the 'world', what world do we have in view? Neither the common world nor the subjective world, but the worldhood of the world as such. By what avenue do we meet this phenomenon?
'Worldhood' is an ontological concept, and stands for the structure of one of the constitutive items of Being-in-the-world. But we know Beingin- the-world as a way in which Dasein's character is defined existentially. Thus worldhood itself is an existentiale. If we inquire onto logically about the 'world', we by no means abandon the analytic of Dasein as a field for thematic study. Ontologically, 'world' is not a way of characterizing those entities which Dasein essentially is not; it is rather a characteristic of Dasein itself. This does not rule out the possibility that when we investigate the phenomenon of the 'world' we must do so by the avenue of entities within-the-world and the Being which they possess. The task of 'describing' the world phenomenologically is so far from obvious that even if we do no more than determine adequately what form it shall take, essential ontological clarifications will be needed.